Abstract

We have proposed and experimentally demonstrated a lithography-free, broadband, thin optical absorber composed of planar multilayered dielectric and metal films, which can cover the total visible wavelength range with simulated and experimental absorption efficiencies higher than 90%. Moreover, the absorption is insensitive to the polarization and angle of incidence. Such a planar device is much easier to fabricate compared with other broadband absorbers with complicated structures and may have potential applications in solar energy harvesting and controllable thermal emission.

The authors acknowledge the support by the National Natural Science Foundation of China (Nos. 91233208, 61271016, and 61178062), the National High Technology Research and Development Program (863 Program) of China (No. 2012AA030402), a Guangdong Innovative Research Team Program (Grant No. 201001D0104799318), and Swedish VR grant (No. 621-2011-4620).